Ensure parent node is always updated in rename(), regardless of fs implementation

src/library_fs.js

@@ -819,6 +819,8 @@ FS.staticInit();` +
         // changed its name)
         FS.hashAddNode(old_node);
       }
+      // update old node (we do this here to avoid each backend needing to)
+      old_node.parent = new_dir;
 #if FS_DEBUG
       if (FS.trackingDelegate['onMovePath']) {
         FS.trackingDelegate['onMovePath'](old_path, new_path);

src/library_memfs.js

@@ -198,7 +198,6 @@ addToLibrary({
         old_node.name = new_name;
         new_dir.contents[new_name] = old_node;
         new_dir.timestamp = old_node.parent.timestamp;
-        old_node.parent = new_dir;
       },
       unlink(parent, name) {
         delete parent.contents[name];

src/library_proxyfs.js

@@ -108,7 +108,6 @@ addToLibrary({
         try {
           oldNode.mount.opts.fs.rename(oldPath, newPath);
           oldNode.name = newName;
-          oldNode.parent = newDir;
         } catch(e) {
           if (!e.code) throw e;
           throw new FS.ErrnoError(ERRNO_CODES[e.code]);